How I Cut Cable Out Of My House

Roku 2 XS Teardown

After waiting for free shipping and processing, I’ve gotten hold of a Roku 2 XS. With it in my hot little hands, it’s time for some poking and prodding.

First Impressions

I gotta hand it to Roku; they made their new box look sexy. It has a very small form factor and is incredibly light. I did notice that the shiny plastic smudges and scratches easily. This doesn’t matter much in my cabinet, but it was a little disappointing since I like to keep things pristine. You might want to keep the protective plastic on it until after everything’s setup.

Now, most people would’ve plugged it in and taken a look at the video quality and streaming performance. While I will get to that, I had a different calling. Like just about other red-blooded, curiosity-seeking engineer, I took it apart.

The Roku 2 is very simply constructed, with just 4 pieces to it. There’s the top and bottom case, the purple back plate, and the PC board. It’s assembled using 4 screws. All the interesting materials are on either side of the PC board.

Roku 2 XS Top Side

The Roku 2 has most (but not all) of the interesting components on the top side. Almost all the external world interface are here, and lots of memory.

The connectors are highlighted in red and blue. Going from bottom left to upper right, we can see the IR remote sensor, USB port, HDMI connector, A/V composite jack, Ethernet jack, and the power plug.

This confirms some findings from Engadget’s article that revealed the Roku 2 box to the world. Specifically, 256 MB DRAM and 256 MB flash.

Roku 2 XS Underside

The bottom side of the board is pretty barren but holds a few curiosities.

For connectors on the bottom of the board, there’s a reset button on the back (a nice change over the Roku XDS which required a power cycle to clean it up flipping it upside down) and the MicroSD memory card slot. Also notable are the “chip” antennas for the WiFi and Bluetooth wireless communications. This change in antenna structure may be related to the rumors of reduced wireless range.

The big metal boxes are shielding around the wireless transmitter / receiver chips. The metal shielding helps with passing FCC requirements to not interfere with other wireless devices. The PC board has markers on it that name the metal boxes as WiFi and Bluetooth areas. Because of the size of the metal plate, I’m assuming that the main processor is paired with the WiFi transmitter in the metal box. Since I’m unwilling to do a destructive teardown on an XS unit to find out, it will have to stay a mystery for now.

What About the Roku 2 Main Processor?

The purported processor, a Broadcom made BCM2835, continues to be source of fascination on the web. Broadcom has not published materials on their website. Fortunately, a small company called Raspberry Pi has turned up and is also using the BCM2835. From their blog, they note that they’re using the BCM2835 with SMSC Ethernet / USB chip to make a simple Linux platform. They’ve identified their provisional specs (which I’m assuming the Broadcom processor meets) as:

700MHz ARM11

128MB or 256MB of SDRAM

OpenGL ES 2.0

1080p30 H.264 high-profile decode

Composite and HDMI video output

USB 2.0

SD/MMC/SDIO memory card slot

Optional integrated 2-port USB hub and 10/100 Ethernet controller

These specs sound like the Roku 2 box. Their language has provided hints that the BCM2835 is a successor to the Broadcom BCM2820 line, an ARM11 based application processor that included Broadcom’s VideoCore video decoding co-processor. The last Roku box used a MIPS architecture for the main processor. The shift from MIPS to ARM is an indication that Roku got something useful out of it, and I’m guessing it was cost. This change would require a major investment in methodology, software, and tool changes to move to the new platform. This also explains my complete miss on new features since I guessed wrong on the main processor and a lot of my predictions were based on the wrong processor.

Conclusions

Roku has put together a low-cost solution that provides some extra computation power for their next solutions. They’ve kept the component count down and have kept the features lean to minimize costs. The extra processing power, plenty of RAM, and OpenGL graphics should help enable the games that they’re touting for their new Roku 2 boxes.